The Clinical Core of the Arizona ADCC is a consortium of five recruitment sites that function as a standardized unit under a single Clinical Core Director. The Clinical Core maintains a target of 500 participants at all stages of the aging-dementia spectrum including 200 normal controls, 100 patients with mild cognitive impairment (MCI), and 200 with Alzheimer's disease (AD) and other forms of degenerative dementia. Embedded within these diagnostic categories are defined Latino and Native American cohorts. The Clinical Core capitalizes on our multi-institutional diagnostic consensus conference, centralized data management program, and close working relationships with each of the other Cores. It is intended to capitalize on our multi-institutional collaborative model, address the challenges associated with a multi-site core, and optimize the utilization of Clinical Core subjects and data in support of the unusually early detection and tracking of AD, our strengths in brain imaging, cognitive neuroscience, neurogenomics, our studies of several putative risk factors, and our participation in several national and international collaboration projects. All subjects undergo standardized diagnostic testing that 1) fulfills strict entrance criteria, 2) includes demographic, historical, medical, neurological, psychiatric, neuropsychological, and genetic measures, 3) incorporates the NACC Uniform Data Set (UDS), and 4) employs culturally sensitive test procedures. Patients eligible for enrollment and those completing annual follow-up are discussed in a biweekly diagnostic consensus conference. All undergo apolipoprotein E (APOE) genotyping at entry, and an annual standardized neuropsychological battery of tests at all sites. Patient eligibility for, and participation in ongoing research projects is tracked and reviewed on an ongoing basis. All are offered enrolled in the Brain Donation Program for neuropathological confirmation of clinical diagnoses, though brain donation is not required of members of culturally sensitive diversity subgroups (Latino and Native Americans). The particular strengths of the Clinical Core include: 1. catchment areas throughout the state of Arizona based on a novel collaborative model that includes all major tertiary care referral centers (BNI, MCA, SHRI, VA, UA) 2. a scientific network of established collaborative relationships between Clinical Core neurologists and biomedical researchers at all major research institutions in Arizona (and elsewhere) 3. a Latino outreach program (through the collaborative efforts of the EIT and Clinical Cores) with a target enrollment of at least 100 dementia/MCI patients and controls 4. a Native American outreach program (through the collaborative efforts of the EIT and Clinical Cores) that encourages the participation of Native Americans in the Clinical Core. 5. ancillary programs of longitudinally studied aging normal controls also receive the NACC UDS supported through other funding mechanisms. These cohorts provide unique opportunities to study the transition between cognitive normality and MCI in persons at differential risk for AD and to capitalize on our strengths in imaging, genomics, cognitive neuroscience, and other research methods. To address the goals of the ADCC, subjects and data from independently funded projects are now available as a resource to other researchers, being used in other studies, and will be followed prospectively using the UDS.